package inter;

public class ChangLiangjie implements  ChangLiang {

    public static void main(String[] args) {
        //猜拳(1.剪刀 2.石头 3 布)
        //交通灯(1.红灯 2.黄灯 3绿灯)


        //状态
        int lightState=RED;//红灯
        //判断
        if (lightState == 1) {
            lightState =GREEN;
        }else if (lightState == 2) {
            lightState =RED;
        }else{
            lightState=YELLOW;
        }
        System.out.println(lightState);
    }
}
interface  ChangLiang{
    public static    final     int RED=1;
    public  static final   int YELLOW=2;
    public    static final    int GREEN =3;
}